# Installation¶

## Before you begin¶

This tutorial assumes that you have already followed the steps in Installing Pyramid, except do not create a virtual environment or install Pyramid. Thereby you will satisfy the following requirements.

## Install SQLite3 and its development packages¶

If you used a package manager to install your Python or if you compiled your Python from source, then you must install SQLite3 and its development packages. If you downloaded your Python as an installer from https://www.python.org, then you already have it installed and can skip this step.

If you need to install the SQLite3 packages, then, for example, using the Debian system and apt-get, the command would be the following:

sudo apt-get install libsqlite3-dev


We will use a cookiecutter to create a Python package project from a Python package project template. See Cookiecutter Installation for instructions.

## Generate a Pyramid project from a cookiecutter¶

We will create a Pyramid project in your home directory for Unix or at the root for Windows. It is assumed you know the path to where you installed cookiecutter. Issue the following commands and override the defaults in the prompts as follows.

### On Unix¶

cd ~


### On Windows¶

cd \


### On all operating systems¶

If prompted for the first item, accept the default yes by hitting return.

You've cloned ~/.cookiecutters/pyramid-cookiecutter-starter before.
Is it okay to delete and re-clone it? [yes]: yes
project_name [Pyramid Scaffold]: myproj
repo_name [myproj]: tutorial
Select template_language:
1 - jinja2
2 - chameleon
3 - mako
Choose from 1, 2, 3 [1]: 1
Select backend:
1 - none
2 - sqlalchemy
3 - zodb
Choose from 1, 2, 3 [1]: 2


## Change directory into your newly created project¶

### On Unix¶

cd tutorial


### On Windows¶

cd tutorial


## Set and use a VENV environment variable¶

We will set the VENV environment variable to the absolute path of the virtual environment, and use it going forward.

### On Unix¶

export VENV=~/tutorial


### On Windows¶

set VENV=c:\tutorial


## Create a virtual environment¶



### On Windows¶

%VENV%\Scripts\pip install --upgrade pip setuptools


## Installing the project in development mode¶

In order to do development on the project easily, you must "register" the project as a development egg in your workspace. We will install testing requirements at the same time. We do so with the following command.



### On Windows¶

%VENV%\Scripts\alembic -c development.ini revision --autogenerate -m "init"


The output to your console should be something like this:

2018-06-22 17:57:31,587 INFO  [sqlalchemy.engine.base.Engine:1254][MainThread] SELECT CAST('test plain returns' AS VARCHAR(60)) AS anon_1
2018-06-22 17:57:31,588 INFO  [sqlalchemy.engine.base.Engine:1254][MainThread] SELECT CAST('test unicode returns' AS VARCHAR(60)) AS anon_1
2018-06-22 17:57:31,589 INFO  [sqlalchemy.engine.base.Engine:1151][MainThread] PRAGMA table_info("alembic_version")
2018-06-22 17:57:31,590 INFO  [sqlalchemy.engine.base.Engine:1151][MainThread] PRAGMA table_info("alembic_version")
CREATE TABLE alembic_version (
version_num VARCHAR(32) NOT NULL,
CONSTRAINT alembic_version_pkc PRIMARY KEY (version_num)
)

2018-06-22 17:57:31,594 INFO  [sqlalchemy.engine.base.Engine:1151][MainThread] SELECT name FROM sqlite_master WHERE type='table' ORDER BY name
Generating /<somepath>/tutorial/alembic/versions/20180622_bab5a278ce04.py ... done




### On Windows¶

%VENV%\Scripts\initialize_tutorial_db development.ini


The output to your console should be something like this:

2018-06-22 17:57:46,241 INFO  [sqlalchemy.engine.base.Engine:1254][MainThread] SELECT CAST('test plain returns' AS VARCHAR(60)) AS anon_1
2018-06-22 17:57:46,242 INFO  [sqlalchemy.engine.base.Engine:1254][MainThread] SELECT CAST('test unicode returns' AS VARCHAR(60)) AS anon_1
2018-06-22 17:57:46,243 INFO  [sqlalchemy.engine.base.Engine:682][MainThread] BEGIN (implicit)
2018-06-22 17:57:46,244 INFO  [sqlalchemy.engine.base.Engine:1151][MainThread] INSERT INTO models (name, value) VALUES (?, ?)
2018-06-22 17:57:46,245 INFO  [sqlalchemy.engine.base.Engine:1154][MainThread] ('one', 1)


Success! You should now have a tutorial.sqlite file in your current working directory. This is an SQLite database with a single table defined in it (models) and single record inside of that.

## Run the tests¶

After you've installed the project in development mode as well as the testing requirements, you may run the tests for the project. The following commands provide options to pytest that specify the module for which its tests shall be run, and to run pytest in quiet mode.



### On Windows¶

c:\tutorial> %VENV%\Scripts\pytest --cov --cov-report=term-missing


If successful, you will see output something like this:

======================== test session starts ========================
platform Python 3.6.5, pytest-3.6.2, py-1.5.3, pluggy-0.6.0
rootdir: /<somepath>/tutorial, inifile: pytest.ini
plugins: cov-2.5.1
collected 2 items

tutorial/tests.py ..
------------------ coverage: platform Python 3.6.5 ------------------
Name                                Stmts   Miss  Cover   Missing
-----------------------------------------------------------------
tutorial/__init__.py                    8      6    25%   7-12
tutorial/models/__init__.py            24      0   100%
tutorial/models/meta.py                 5      0   100%
tutorial/models/mymodel.py              8      0   100%
tutorial/routes.py                      3      3     0%   1-3
tutorial/scripts/__init__.py            0      0   100%
tutorial/scripts/initialize_db.py      24     24     0%   1-34
tutorial/views/__init__.py              0      0   100%
tutorial/views/default.py              12      0   100%
tutorial/views/notfound.py              4      4     0%   1-7
-----------------------------------------------------------------
TOTAL                                  88     37    58%

===================== 2 passed in 0.57 seconds ======================


Our package doesn't quite have 100% test coverage.

## Test and coverage cookiecutter defaults¶

Cookiecutters include configuration defaults for pytest and test coverage. These configuration files are pytest.ini and .coveragerc, located at the root of your package. Without these defaults, we would need to specify the path to the module on which we want to run tests and coverage.



### On Windows¶

%VENV%\Scripts\pserve development.ini --reload


Note

Your OS firewall, if any, may pop up a dialog asking for authorization to allow python to accept incoming network connections.

If successful, you will see something like this on your console:

Starting subprocess with file monitor
Starting server in PID 44078.
Serving on http://localhost:6543
Serving on http://localhost:6543


This means the server is ready to accept requests.

## Visit the application in a browser¶

In a browser, visit http://localhost:6543/. You will see the generated application's default page.

One thing you'll notice is the "debug toolbar" icon on right hand side of the page. You can read more about the purpose of the icon at The Debug Toolbar. It allows you to get information about your application while you develop.

## Decisions the cookiecutter backend option sqlalchemy has made for you¶

When creating a project and selecting the backend option of sqlalchemy, the cookiecutter makes the following assumptions:

• You are willing to use SQLite for persistent storage, although almost any SQL database could be used with SQLAlchemy.
• You are willing to use SQLAlchemy for a database access tool.
• You are willing to use Alembic for a database migrations tool.
• You are willing to use a console script for a data loading tool.
• You are willing to use URL dispatch to map URLs to code.
• You want to use zope.sqlalchemy, pyramid_tm, and the transaction packages to scope sessions to requests.

Note

Pyramid supports any persistent storage mechanism (e.g., object database or filesystem files). It also supports an additional mechanism to map URLs to code (traversal). However, for the purposes of this tutorial, we'll only be using URL dispatch and SQLAlchemy.